In June 2012 in IA it was
Bachmann 21% (won straw poll)
Romney 20%
RuPaul 18%
Shortly after the Straw Poll and after Rick Perry’s Entry, but before Perry had the “3 points” debate meltdown
Perry 19%
Romney 18%
RuPaul 18%
After Perry’s fall to the wayside and Herman Cain’s 9-9-9
but before Romney’s insiders and pals in NJ did him in with the made up scandals
Cain 20%
Romney 20%
RuPaul 19%
After Newt comes out of nowhere and surges right before Christmas but before he dropped back down again after comments during the week before the Caucus
Romney 23%
Newt 21%
RuPaul 18%
Caucus day. Rick Santorum griped about being the only one not to get a chance to surge. The surge happened a little unexpectedly on Election day and gave him a 25 vote win.
Santorum 25%
Romney 25%
RuPaul 20%
So Polls at this stage are meaningless.
The only generalization we can make is that IA has roughly 25% of RINO voters, about 20-30% Social Issues only conservatives, 15-20% libertarians that may or may not actually be as insane as RuPaul and 20-25% up for grabs that gets distributed to the other candidates.
This means a Republican that wins IA in a crowded field with 40% or more of the vote looks strong.
Describes Iowa caucuses perfectly. Nothing is determined by the caucus straw vote. Delegates selected to the county and district can't be committed to a candidate. That's why Iowa can go so early.